Seismic Behavior Of Buckling Restrained Structures In Long Span Structures

The cantilever structure is usually static,fixed at one end and free at one end,Therefore,when the span of the cantilever is larger or the vertical force is larger,a larger bending moment and shear can occur at the fixed end,The traditional design method of the structure to improve its strength and stiffness to resist the earthquake,but the consequences of structural element sections to increase use will affect the structure of the space,at the same time simply to improve the strength and stiffness of the structure but also to bring greater seismic response.The principle of energy dissipation technology is to dissipate part of the seismic energy under the earthquake action by using the energy dissipation device,so as to reduce the structural seismic response and protect the main structure,BRB is a new type of energy dissipation member,It can play a good hysteretic performance and consume seismic energy under the action of large earthquake.Compared with ordinary steel braces,BRBs has no pressure buckling instability condition,and has better safety.In this paper,the influence of BRBs on the seismic behavior of long-span cantilevered structures is studied based on a large-span cantilevered structure engineering case,which provides some reference for similar structures in aseismic design.In this paper,the energy dissipation technology,the long-span cantilever structure and the BRBs are introduced,describes the basic principle of anti shock technology and its superiority in seismic design of the large-span cantilevered structure characteristics are summarized,in-depth understanding of the BRBs from buckling restrained braced structure and working mechanism,research status at home and abroad.Secondly,the analysis method of BRB system is introduced in detail.Based on that,a finite element model of a steel braced structure and three different forms of BRB structure is established by using Midas software.The elastic and elasto-plastic seismic analysis of the model is carried out.Finally,based on the above analysis,the layout of BRBs is optimized,and a new BRB model is established.The seismic performance of the model is compared with that of the steel bracing model under Pushover.The above analysis results show that:(1)The BRB is still in the elastic stage under the action of small earthquakes,and it can only play the same role as ordinary steel support.(2)The BRBs can enter the yield stage earlier than the ordinary steel support under the rare earthquake.It consumes the seismic energy and exhibits good hysteretic performance.It effectively reduces the seismic response of the cantilever structure and protects the main structure.(3)The layout of BRBs has a certain degree of influence on the seismic performance of structures,and the performance of hysteretic behavior is different for the same position with different brace layout.(4)Pushover analysis showed that the structure of the BRB with severe earthquake,vertex displacement,base shear and layer displacement angle decreases,and BRBs not buckling,the hysteretic behavior of the BRBs has an obvious effect on reducing the damage degree of the beam and column in the main structure,and improves the seismic performance of the structure.